To: andrew@pillette.com
Cc: pgsql-sql@postgresql.org
Subject: Re: CREATE RULE ignored, what did I do wrong 
In-reply-to: <200409102136.i8ALajP19402@pillette.com> 
References: <200409102136.i8ALajP19402@pillette.com>
Comments: In-reply-to andrew@pillette.com
	message dated "Fri, 10 Sep 2004 14:36:45 -0700"
Date: Sat, 11 Sep 2004 02:42:23 -0400
Message-ID: <7805.1094884943@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

andrew@pillette.com writes:
> Foreign-key constraints:
>     "$1" FOREIGN KEY (smoothing_id) REFERENCES smoothing_algorithm(smoothing_id) ON UPDATE CASCADE ON DELETE CASCADE
> Rules:
>     del_smoothed_rank_episode AS ON DELETE TO smoothed_rank_episode
> WHERE (NOT old.is_deleted) DO INSTEAD ...

The DELETE commands generated by the foreign key ON DELETE CASCADE will
get rewritten by your ON DELETE rule.  You probably do not want to do
this; or at least not make it an INSTEAD rule.

There has been some debate in the past about whether rules should be
able to break foreign-key constraints, but I tend to class it as a
"you should know what you're doing" feature.  Preventing this kind
of error would inevitably result in a serious reduction of the power
of the rule feature.

			regards, tom lane